[填空题]
(a) If a volcano spe an(+t fi.wr 9 ek030vzd9- fns)ftwshws a 500-kg ro 8():1bf t35cdolmlbovj i-ngck vertically upward a distance of 500 m, what was its velocity when it left tc8ib:obgf53 -(mn l1o)ljdt v he volcano? m/s
(b) If the volcano spews the equivalent of 1000 rocks of this size every minute, what is its power output? W a = b =